The biological association between obesity and colorectal cancer has been demonstrated in a new scientific paper published in Cancer Research.
The heightened risk of colorectal cancer allegedly caused by obesity has been the subject of previous studies, but, has nevertheless remained elusive. Obese people are much likely to develop colorectal cancer: they have a 50% greater risk than the average person. Why is this the case?
How are the two linked? The new research conducted by scientists from the Thomas Jefferson University has succeeded in showing the connection. Furthermore, the team has proposed a drug that might halt the spread of the cancer.
As per the results of experiments conducted on mice, the expression of an important hormone acting in the intestinal epithelium (guanylin) was found to be switched off by a high-calorie diet; also, obese people have an 80% decrease in the gene expression of guanylin. Normally, when the hormone turns its receptor on, epithelium regeneration processes are regulated. On the other hand, the consequences of it being turned off is that a tumour suppressor pathway is deactivated as the researchers also discovered that the role of the hormone receptor is to control growth and suppress tumours. In absence of the hormone, the receptor does not do its job. Eventually, the epithelium does not function properly and favours cancer development.
Fortunately, the team also discovered that the problem can be countered through hormone replacement therapy so that the tumour suppressor is turned on again – an ‘intervention’ that stopped the cancer from developing in spite of the mice eating an excessive amount of calories. This is the case because while the hormone itself is lost, its receptor is still there, and this is why the drug works.
Study author Scott Waldman says that the pill known as linaclotide (Linzess) which shares similar structural characteristics to the hormone can be used to protect obese patients from the cancer.
It is to be noted that the drug is an FDA-approved one since 2012. It is normally used for treatment of irritable bowel syndrome with constipation.
Dr Waldman is currently testing the dose and potential side effects of the drug in human volunteers.